An apparatus and methods for thermally treating webs having thermoplastic respectively meltable compounds, thereby creating cylindrical or elliptic consolidation regions which may optionally have an aperture by employing a thermal energy source, such as ultrasonic energy, as well as to webs with elliptic consolidation regions. In a particular, the apparatus and methods create consolidation regions by using an anvil with a flexible elongated member, such as a wire, a chain or a tubular anvil with circumferential ribs.